Hello everyone! I'm new to this so please bear with me. I have a battery charger connected in my RV to maintain the batteries. Problem is: If I try to use the 12v radio, I get a hum if the charger is on. Sounds like 60 cycle, but I'm not sure. There is a .22v AC component with the charger on the low (3A) setting, ~.5v AC at the 10 amp setting. Is there a way to filter this, or should I just buy one of the new "smart chargers"? I've looked at the Rectifier/Filter circuit in the Volume VI experiments. Will this work? Any help would be appreciated!